Nanotechnology aids large-area solar cell

NETANYA, Israel  A scientist at Israel's Bar-Ilan University claims that he has managed to create a solar cell 100 times bigger than a typical solar cell, using nanotechnology methods.
Professor Arie Zaban, head of Bar-Ilan University's Nanotechnology Institute, is an expert in photovoltaics. In a recently patented technique, Professor Zaban demonstrated how metallic wires mounted on conductive glass can form the basis of solar cells with efficiency similar to that of conventional, silicon-based cells, but that are much cheaper to produce.

While Professor Zaban's earlier efforts produced photovoltaic cells one square centimeter in size, he has now achieved a cell measuring 10 centimeters by 10 centimeters, which he claimed would boost the technique's usefulness in producing commercial amounts of solar power.
"Initially, we created linked arrays of very small cells, which led to a loss of efficiency because the sunlight hitting the space between the cells was not converted to electricity," Professor Zaban said. Professor Zaban said the cell is now a practical choice for solar energy production.
"We've found a way to produce platinum nanodots – tiny crystals measuring only a few nanometers in diameter," Professor Zaban said, adding that this highly reactive metal is an important part of his solar cell's operation. "Thanks to this technique – now under consideration for a patent – we reduce the amount of platinum needed by a factor of 40."
In previous research, Professor Zaban developed a low-cost method of depositing semiconductor material in a sponge-like array on top of flexible plastic sheets. Key to his system is the use of an organic dye that allows the semiconductor, transparent in its natural form, to absorb light.

"Cost is an important factor in the success of any solar technology," Professor Zaban said. "To become widely adopted, solar cells must generate electricity at lower cost than what we now spend on fossil fuels. At the same time, we have to make the basic infrastructure extremely affordable because the third-world countries that stand to reap the most benefit from solar power usually lack the money to invest in it. By making cells more efficient and keeping material costs down, nano-based techniques are moving us closer to that goal."
Professor Zaban serves as an advisor to Orion Solar, a Jerusalem-based company that has entered into partnership with Bar-Ilan University and is developing commercial applications for inexpensive, dye-based photovoltaics based on his work. "Given the state of the technology, I believe that the new solar cells will be available commercially within the next five years," he said.